Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual transportadora está classificada em 20º lugar?
 ###Tabelas: CREATE TABLE busiest_international_routes (busiest_international_routes_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Airport VARCHAR, Passengers INT, Aircraft Movements INT, Carriers VARCHAR) CREATE TABLE 2013–14_season (2013–14_season_id AUTO_INCREMENT PRIMARY KEY, Club VARCHAR, Position in 2012–13 VARCHAR, First season in top division VARCHAR, Number of seasons in top division INT, First season of current spell in top division VARCHAR, Top division titles INT, Last top division title VARCHAR) CREATE TABLE mlb_draft_history (mlb_draft_history_id AUTO_INCREMENT PRIMARY KEY, Draft Year INT, Player VARCHAR, Summer Team VARCHAR, College VARCHAR, MLB Team VARCHAR, Draft Round VARCHAR) CREATE TABLE currently_proposed (currently_proposed_id AUTO_INCREMENT PRIMARY KEY, Stadium VARCHAR, Capacity INT, City VARCHAR, Country VARCHAR, Tenant VARCHAR, Opening VARCHAR) CREATE TABLE season_20:_2012-2013 (season_20:_2012-2013_id AUTO_INCREMENT PRIMARY KEY, Series Ep. VARCHAR, Episode INT, Segment A VARCHAR, Segment B VARCHAR, Segment C VARCHAR, Segment D VARCHAR)  
SELECT Carriers FROM busiest_international_routes WHERE Rank = 20